Objective: SW1990-spheroid enrichment (SW1990-SE) cells were isolated using a new type of consecutive spheroid enrichment in this study. Cell surface markers were determined by flow cytometry for identification. In vivo tumorigenicity was applied by subcutaneous transplantation in nude mice for verifying the stemness characteristics of SW1990-SE cells.
Materials and methods: SW1990-SE cells were subjected to lentivirus infection for establishing the SW1990-SE cell line stably low-expressing HCCS1 (SW1990-SE-shHCCS1) and negative control cell line (SW1990-SE-LV3NC). The stemness regulatory effects of HCCS1 on SW1990-SE cells were evaluated by cell counting kit-8 (CCK-8) assay and 96-wells plate single cell cloning assay in vitro. Subcutaneous transplantation in nude mice was conducted for evaluating the in vivo stemness regulation of HCCS1 on SW1990-SE cells..
Results: HCCS1 knockdown in SW1990-SE cells did not markedly change the cell proliferation and doubling time, whereas the in vitro spheroid diameter and single cell cloning efficacy remarkably increased. In vivo experiments showed that HCCS1 knockdown greatly enhanced the tumorigenicity of SW1990-SE cells in nude mice.
Conclusions: This study first obtains the human pancreatic cancer stem-like cells SW1990-SE through consecutive spheroid enrichment. Both in vivo and in vitro experiments verified that HCCS1 knockdown largely enhanced the stemness of SW1990-SE cells. Our study provides an important reference for the research of tumor stem cells.